1 files changed, 62 insertions, 0 deletions
diff --git a/lib/puppet/transaction/resource_harness.rb b/lib/puppet/transaction/resource_harness.rb
new file mode 100644
index 000000000..da859910c
--- /dev/null
+++ b/lib/puppet/transaction/resource_harness.rb
@@ -0,0 +1,62 @@
+require 'puppet/resource/status'
+
+class Puppet::Transaction::ResourceHarness
+    extend Forwardable
+    def_delegators :@transaction, :relationship_graph
+
+    attr_reader :transaction
+
+    def allow_changes?(resource)
+        return true unless resource.purging? and resource.deleting?
+        return true unless deps = relationship_graph.dependents(resource) and ! deps.empty? and deps.detect { |d| ! d.deleting? }
+
+        deplabel = deps.collect { |r| r.ref }.join(",")
+        plurality = deps.length > 1 ? "":"s"
+        resource.warning "#{deplabel} still depend#{plurality} on me -- not purging"
+        return false
+    end
+
+    def apply_changes(status, changes)
+        changes.each do |change|
+            status << change.apply
+        end
+        status.changed = true
+    end
+
+    def changes_to_perform(status, resource)
+        current = resource.retrieve
+
+        if param = resource.parameter(:ensure)
+            insync = param.insync?(current[:ensure])
+            return [Puppet::Transaction::Change.new(param, current[:ensure])] unless insync
+            return [] if param.should == :absent
+        end
+
+        resource.properties.reject { |p| p.name == :ensure }.find_all do |param|
+            ! param.insync?(current[param.name])
+        end.collect do |param|
+            Puppet::Transaction::Change.new(param, current[param.name])
+        end
+    end
+
+    def evaluate(resource)
+        status = Puppet::Resource::Status.new(resource)
+
+        if changes = changes_to_perform(status, resource) and ! changes.empty?
+            status.out_of_sync = true
+            apply_changes(status, changes)
+            resource.cache(:synced, Time.now)
+            resource.flush if resource.respond_to?(:flush)
+        end
+        return status
+    rescue => detail
+        resource.fail "Could not create resource status: #{detail}" unless status
+        resource.err "Could not evaluate: #{detail}"
+        status.failed = true
+        return status
+    end
+
+    def initialize(transaction)
+        @transaction = transaction
+    end
+end